Showing posts with label TESS. Show all posts
Showing posts with label TESS. Show all posts

Wednesday, September 14

A New Class of ExoPlanet




Artist's illustration of a half-rock, half-water world orbiting a red dwarf star. 
(Image credit: Pilar Montañés (@pilar.monro))







A new type of exoplanet — one made half of rock and half of water — has been discovered around the most common stars in the universe, which may have great consequences in the search for life in the cosmos, researchers say.


Red dwarfs are the most common type of star, making up more than 70% of the universe's stellar population. These stars are small and cold, typically about one-fifth as massive as the sun and up to 50 times dimmer.

The fact that red dwarfs are so very common has made scientists wonder if they might be the best chance for discovering planets that can possess life as we know it on Earth. For example, in 2020, astronomers that discovered Gliese 887, the brightest red dwarf in our sky at visible wavelengths of light, may host a planet within its habitable zone, where surface temperatures are suitable to host liquid water.

However, whether the worlds orbiting red dwarfs are potentially habitable remains unclear, in part because of the lack of understanding that researchers have about these worlds' composition. Previous research suggested that small exoplanets — ones less than four times Earth's diameter — orbiting sun-like stars are generally either rocky or gassy, possessing either a thin or thick atmosphere of hydrogen and helium.


In the new study, astrophysicists sought to examine the compositions of exoplanets around red dwarfs. 

They focused on small worlds found around closer — and thus brighter and easier to inspect — red dwarfs observed by NASA's Transiting Exoplanet Survey Satellite (TESS).  READ MORE...

Thursday, May 20

New Exoplanet

A team of astronomers from the Grenoble Alpes University in France and elsewhere, reports the detection of a new sub-Neptune exoplanet orbiting an M dwarf star. The newly found alien world, designated TOI-269 b, is nearly three times larger than the Earth. The finding was detailed in a paper published April 30 on the arXiv pre-print repository.

NASA's Transiting Exoplanet Survey Satellite (TESS) is conducting a survey of about 200,000 of the brightest stars near the sun with the aim of searching for transiting exoplanets. So far, it has identified nearly 2,700 candidate exoplanets (TESS Objects of Interest, or TOI), of which 125 have been confirmed so far.

TOI-269 (also known as TIC 220479565) is an M dwarf located some 186 light years away from the Earth. It has a spectral type of M2V, radius of about 0.4 solar radii and mass of approximately 0.39 solar masses. The star's effective temperature is estimated to be some 3,500 K, while its metallicity is at a level of around -0.29.269

TOI-269 was observed by the TESS spacecraft between September 2018 and July 2019, which resulted in the identification of a transit signal in its light curve. Now, using various ground-based telescopes, including the Exoplanets in Transits and their Atmospheres (ExTrA) facility at La Silla Observatory in Chile, a group of astronomers led by Marion Cointepas has confirmed the planetary nature of this signal.  TO READ MORE, CLICK HERE...